Vehicle mounted sprayers of various types are well known for spraying liquids used for growing and maintaining a healthy turf surface or for other horticultural purposes. Such vehicle mounted sprayers are particularly useful for spraying large turf areas that would be too time consuming to treat with handheld or walk behind sprayers.
In order to increase the width of the spray, many vehicle mounted sprayers include a center boom that is fixed to the vehicle. A pair of wing booms are pivotally attached to each end of the center boom. In a spraying position, the wing booms are extended horizontally outward from and laterally aligned with the center boom so that the spray width is often substantially larger than the width of the vehicle. In this case, the outer ends of the wing booms stick laterally outwardly beyond the lateral wheelbase of the vehicle.
In sprayers with a pair of wing booms, the wing booms can typically be folded into a transport position to decrease the width of the sprayer. This allows the sprayer to fit through narrower spaces or to be transported along a roadway. Some sprayers fold the wing booms in horizontal planes until the wing booms extend longitudinally flush along each side of the vehicle. Other sprayers fold the wing booms vertically with the wing booms sticking upwardly at each side of the vehicle. The net result in either case is to decrease the width of the sprayer.
When the wing booms fold vertically, they extend upwardly quite high which can lead to various problems. For example, if the wing booms are long, they can extend so high when folded up that they would strike low lying branches or be unable to pass through restricted height spaces, such as tunnels. This problem can be somewhat alleviated, but not entirely eliminated, by folding the booms into an X-shaped transport position where each wing boom crosses over the other wing boom. This lowers the height of the upper ends of the wing booms at least somewhat from the height they would have if the wing booms projected purely vertically.
However, when folding the wing booms vertically into an X-shaped transport position, the wing booms must also be displaced longitudinally to avoid hitting one another. This has been done in some cases in the past by having relatively complicated pivot structures. It would be an advance in the art to be able to fold the wing booms into an X-shaped transport position using a simple, durable pivot.
Another problem with known sprayers is the possibility of damage to the folded wing booms due to impact with low-overhead objects while the wing booms are in their transport positions during a transport event. The state of the art is that the wing booms will often bend or break as a result of this type of impact. This is obviously not desirable.
Another problem with known sprayers is the possibility of damage when the wing booms are in their horizontal, extended spraying position. Because the wing booms stick outwardly well beyond the sides of the vehicle, and because it can be difficult to judge the clearance between the ends of the wing booms and an obstacle, it is not unusual for the operator to drive the ends of the wing booms into an obstacle, such as a tree or post. This impact can damage the wing boom and/or the obstacle struck by the wing boom. In the case of a tree, the wing boom can scar or damage the tree in such a way that its appearance is permanently marred or its health impaired significantly enough to require replacement of the tree. Either result is unfortunate.
Sprayers attempt to mitigate this problem by allowing the wing boom to pivot or breakaway if the wing boom strikes an obstacle. However, this is most often done only if the wing boom strikes an obstacle when the vehicle is moving forwardly. If the wing boom strikes an obstacle during reverse motion of the vehicle, there usually is no similar breakaway feature. Thus, it would be a further advance in the art to provide a wing boom with bi-directional breakaway capability.
In addition, when a wing boom breaks away, it must be reset into its usual position to resume spraying. In some wing booms that breakaway, this must be done manually by the operator. Obviously, this is a time consuming and onerous process since the operator must stop the vehicle, dismount the vehicle, reset the wing boom, and then remount and start the vehicle to resume spraying. A wing boom that is self-resetting using a simple and durable breakaway structure would also be desirable.
Finally, to the extent that the obstacle that causes the wing boom to breakaway is a tree or plant, there will be some contact between the wing boom and the tree or plant even if the wing boom breaks away. In fact, it is this contact that provides the force required to pivot the wing boom during a breakaway operation. The tree or plant can still be damaged as result of this contact. It is desirable to minimize the chance of any significant damage by making the outer end of the wing boom more tree or plant friendly.